doc_ai_frontend/docs/MULTILANG_README.md

# 多语言支持说明 / Multi-language Support

## 概述 / Overview

TexPixel 现在支持完整的中英文双语切换，包括：
- 动态页面标题和 meta 标签更新
- SEO 优化的多语言支持
- 智能语言检测（基于 IP 和浏览器偏好）

TexPixel now supports complete bilingual switching between Chinese and English, including:
- Dynamic page title and meta tag updates
- SEO-optimized multi-language support
- Intelligent language detection (based on IP and browser preferences)

---

## 功能特性 / Features

### 1. 自动语言检测 / Automatic Language Detection

应用会按以下优先级检测用户语言：
1. localStorage 中保存的用户选择
2. IP 地理位置检测
3. 浏览器语言设置

The app detects user language in the following order of priority:
1. User's saved preference in localStorage
2. IP geolocation detection
3. Browser language settings

### 2. SEO 优化 / SEO Optimization

- **hreflang 标签**：告知搜索引擎不同语言版本的页面
- **多语言 meta 标签**：description、keywords、og:locale 等
- **动态标题更新**：切换语言时自动更新页面标题

Features include:
- **hreflang tags**: Inform search engines about different language versions
- **Multilingual meta tags**: description, keywords, og:locale, etc.
- **Dynamic title updates**: Automatically update page title when switching languages

### 3. Open Graph 和 Twitter Cards

支持社交媒体分享的多语言 meta 标签：
- Facebook (Open Graph)
- Twitter Cards
- 其他支持 OG 协议的平台

Multilingual meta tags for social media sharing:
- Facebook (Open Graph)
- Twitter Cards
- Other platforms supporting OG protocol

---

## 技术实现 / Technical Implementation

### 文件结构 / File Structure

```
src/
├── lib/
│   ├── seoHelper.ts          # SEO 元数据管理 / SEO metadata management
│   ├── translations.ts        # 翻译文本 / Translation texts
│   └── ipLocation.ts          # IP 定位 / IP location detection
├── contexts/
│   └── LanguageContext.tsx    # 语言上下文 / Language context
└── components/
    └── Navbar.tsx             # 语言切换器 / Language switcher
```

### 核心函数 / Core Functions

#### `updatePageMeta(language: Language)`
更新页面的所有 SEO 相关元数据，包括：
- document.title
- HTML lang 属性
- meta description
- meta keywords
- Open Graph 标签
- Twitter Card 标签

Updates all SEO-related metadata on the page, including:
- document.title
- HTML lang attribute
- meta description
- meta keywords
- Open Graph tags
- Twitter Card tags

#### `getSEOContent(language: Language)`
获取指定语言的 SEO 内容（标题、描述、关键词）

Get SEO content for a specific language (title, description, keywords)

---

## 使用方法 / Usage

### 在组件中使用语言功能 / Using Language Features in Components

```typescript
import { useLanguage } from '../contexts/LanguageContext';

function MyComponent() {
  const { language, setLanguage, t } = useLanguage();
  
  return (
    <div>
      <h1>{t.common.title}</h1>
      <button onClick={() => setLanguage('en')}>English</button>
      <button onClick={() => setLanguage('zh')}>中文</button>
    </div>
  );
}
```

### 添加新的翻译文本 / Adding New Translation Texts

在 `src/lib/translations.ts` 中添加：

```typescript
export const translations = {
  en: {
    myFeature: {
      title: 'My Feature',
      description: 'Feature description',
    }
  },
  zh: {
    myFeature: {
      title: '我的功能',
      description: '功能描述',
    }
  }
};
```

---

## 最佳实践 / Best Practices

1. **始终提供双语内容** / Always provide bilingual content
   - 确保所有用户可见的文本都有中英文翻译
   - Ensure all user-visible text has Chinese and English translations

2. **保持 SEO 元数据最新** / Keep SEO metadata up-to-date
   - 在 `seoHelper.ts` 中维护准确的页面描述和关键词
   - Maintain accurate page descriptions and keywords in `seoHelper.ts`

3. **测试语言切换** / Test language switching
   - 确保切换语言时页面标题和 meta 标签正确更新
   - Ensure page title and meta tags update correctly when switching languages

4. **考虑 RTL 语言** / Consider RTL languages
   - 虽然目前只支持中英文，但代码架构支持未来添加其他语言
   - While currently supporting only Chinese and English, the architecture supports adding other languages in the future

---

## 路线图 / Roadmap

- [ ] 添加更多语言支持（日语、韩语等）/ Add more language support (Japanese, Korean, etc.)
- [ ] 实现 URL 路由多语言 (/en, /zh) / Implement URL routing for languages
- [ ] 服务端渲染 (SSR) 支持 / Server-side rendering (SSR) support
- [ ] 语言特定的日期和数字格式化 / Language-specific date and number formatting

---

## 相关链接 / Related Links

- [hreflang 标签最佳实践](https://developers.google.com/search/docs/specialty/international/localized-versions)
- [Open Graph Protocol](https://ogp.me/)
- [Twitter Cards Documentation](https://developer.twitter.com/en/docs/twitter-for-websites/cards/overview/abouts-cards)